1. Field of the Invention
The present invention relates to the field of small storage canisters for raw food articles. More particularly the present invention relates to the field of small airtight storage canisters for raw food articles.
2. Description of the Prior Art
Small storage canisters are often used in kitchens for storing raw food articles such as flour, sugar, granola and coffee beans. One important criteria for those canisters is whether it is airtight or not. Some raw food articles, such as coffee beans, are better stored under airtight conditions to preserve their preferred qualities including natural flavors, freshness, and sometimes even, dryness.
Airtight and non-airtight canisters are very different. Airtight canisters usually require a more complicated closure mechanism to ensure the airtightness. Although airtight canisters are made of many kinds of materials, including ceramic, wood, glass and acrylic, with numerous variations in their shapes and sizes, there are only a few different mechanical designs for the airtight closure means currently available on the market.
A typical covered canister comprises a container and a cover. The container and the cover are often made of the same material such as ceramic, wood, glass and acrylic. The container is usually cylindrical shaped with a closed bottom and an open top. For non-airtight canisters the cover is merely resting over the open top of the container. For airtight canisters, the cover cannot just rest on the open top of the container. One way to ensure the airtightness is to add a sealing gasket or washer between the cover and the open top of the container. Another way to ensure the airtightness is to employ some kind of mechanical means to tightly attach the cover to the open top of the container.
Although there are many mechanical means available, the application of the small airtight canisters as normal housewares requires that the mechanical means be simple and easy to produce and operate. There are two common types of conventional airtight covering means commonly used for small housewares. One common type of conventional airtight canister utilizes various types of screw means for attaching the cover and the container. The disadvantage of this type of canister closure that it requires extra effort to operate the screw means. Another common type of conventional airtight canister closure mechanism comprises a wire around the cover and another wire around the open top of the container. The two wires are usually metal wires. At the front of the canister the two wires are attached by a leverage tab which also can be made of metal wires. At the rear of the canister the two wires are either hingeably attached by a hinge means or detachably attached by another leverage tab. The disadvantage of this type of conventional canister closure mechanism is that the leverage tabs are sometimes difficult to use, especially for those elderly people with less strength in their hands.
Recently there is a new design airtight canister with the trade name CLICK CLACK. It has two mechanical squeezable tabs in the center of a cover tightly fitted on a container which, when squeezed, reduces the diameter of the cover to therefore allow it to be removed from the container. This product is available only in acrylic. The drawback, however, is that for some kinds of raw food articles the canisters made of acrylic are not suitable. For example, acids in coffee beans can hurt the surface of acrylic containers. It is preferable to use traditional glass or ceramic containers which resist harsh materials in some raw food articles.